Japanese Unexamined Patent Application Publications No. 11-34710 and No. 2005-59646 each disclose a seat with a seating sensor which includes a pad main body having a concave portion in its bottom dented upward, a slab placed in the concave portion, and a sensor arranged on a top face of the slab.
Japanese Unexamined Patent Application Publication No. 2004-255208 mentions a seat cushion including a pan frame and a seat cushion pad made of a polyurethane foam and arranged on the pan frame, in which the pan frame includes holes below an ischium-contact section so as to yield a soft seating feel in the vicinity of the ischium-contact section.
Patent Document 1: Japanese Unexamined Patent Application Publication No. 11-34710
Patent Document 2: Japanese Unexamined Patent Application Publication No. 2005-59646
Patent Document 3: Japanese Unexamined Patent Application Publication No. 2004-255208